OPA2228 sounds like an alternative try, not much better or worse on paper.
LME49720 and LME49860 do have better characteristics on paper and a lot of people enjoy the transparency so you might also try those.

Everything seems OK electronically. In this case, I think the opamp choice was made to give a "forgiving sound" since the unit is intended to be a playable instrument.

Indeed, the original opamp in all its "warmth" (tee hee) was hiding a minor resonant peak in the high midrange that comes out in certain circumstances. So, TL072 might have been chosen as a cover-up in addition to being inexpensive.